I want to download old Skype attachment files.

There is no new endpoint documented for downloading legacy Skype AMS attachments after the Skype-to-Teams migration. Attachments referenced by AMS Object IDs continue to be served from the same Skype/Bot Framework attachment service endpoints and require valid authentication.

The only supported, documented way to retrieve historical Skype files now is via the Skype data export flow:

1. Go to the Skype Export page and sign in with the same Microsoft account used in Skype.
2. Request an export including Files (and Conversations if needed).
3. When the export is ready, download the .tar archive from Available Exports.
4. Extract the .tar file (for example, on Windows 10/11 using tar -xvf YOURFILENAME_export.tar in Command Prompt) to access the exported media.

If the file is not present in the exported media, or AMS endpoints return Unauthorized, there is no supported alternative endpoint to retrieve that attachment.

For Azure bots used in Omnichannel scenarios, AMS attachments can still be downloaded using the documented Bot Framework attachment endpoint pattern with a valid bot token, but this applies only to Azure bot/Omnichannel integrations, not to consumer Skype history:

string requestUri = $"https://botapi.skype.com/amer/v3/attachments/{attachmentId}/views/original";
var httpRequest = new HttpRequestMessage(HttpMethod.Get, requestUri);

var authorization = new AuthenticationHeaderValue("bearer", <botToken>);
httpRequest.Headers.Authorization = authorization;
httpRequest.Headers.Add("BotAcsId", activity.Recipient.Id);

HttpResponseMessage response = await client.SendAsync(httpRequest);

If AMS returns Unauthorized and the file is also missing from the official export, the attachment is no longer retrievable via supported APIs.

References:

• How do I export or delete my Skype data?
• Skype is retiring in May 2025: What you need to know
• Skype help & learning
• Download file attachments from an Azure bot